Objective. A study is made of the efficacy of the Erbium:YAG laser in granulomatous periapical lesions, based on clinical and radiographic controls. Material and methods. The study comprised a series of 45 patients amenable to periapical surgical treatment of incisors, canines and premolars. A conventional surgical technique was used, with silver amalgam retrograde filling and irradiation of the bone defect and remnant root cement with the Erbium:YAG laser. Clinical and radiographic controls were made during 24 months, assessing the absence of symptoms and the presence of pain, swelling or fistula and ossification of the lesions, respectively. Results. The clinical course proved asymptomatic in 95.5% of the cases. As regards remodeling of the bone cavity, 77.7% had completed ossification after 24 months, 13.3% were in an advanced stage of ossification and 4.5% in an intermediate stage, while 4.5% showed treatment failure. Conclusions. The combination of silver amalgam and irradiation with the Erbium:YAG laser in periapical surgery showed a very high clinical success rate, with a 77.7% bone cavity remodeling rate after 24 months.